northern michigan, to giants stadium in new jersey, and to a farm outside detroit where in 2006 the fbi raised a 3,000 foot barn and dug under it. once the leader of the teamsters, the nash's largest union, his connection with organized crime kept him in hot water. >> i believe the stories that hoffa was in a power struggle. i believe hoffa was killed by organized crime figures. >> reporter: that possibility could explain the informant's long silence. >> i mean, he is terrified. i could hear his voice tremble yesterday when i talked to him. >> reporter: could this be where the search for hoffa ends? >> we are investigating it as a cold case homicide. that's been our focus since the beginning. if it somehow happens to be mr. hoffa, great, it will end a major mystery. >> reporter: police say the work here will take about two hours. they're going to take that core soil sample, send it to a forensic anthropologist at michigan state university. if the examination of that soil sample turns up evidence of remains, then they'll start digging. willie? >> john yang, thanks so much. 7:20. here is